In addition to injecting gentamycin, there is also a labyrinthectomy, where they would take out the balance organ and nerve, but not the tumor. Less invasive, no risk of facial nerve issue. But either treatment would most likely take out the hearing on that side, and full AN surgery has a pretty high chance of doing so as well, especially as you describe the AN as wrapped around the eighth nerve. So you get the conundrum: is it worth giving up the hearing to fix the balance?
I would pursue those vestibular exercises with a vengeance, and take Ibuprofen and steroids and anything else, to see if you can get to a point where the balance situation is manageable and you still have your perfect hearing. If you could switch it around and have 90% good time and 10% battling balance, it might be good enough.
That is my nickel's worth (inflation, you know). I hope something works out well.
Steve
